(9  &  3*^1 


University  Bulletin 


Series  8— No.  28 


Agricultural  Series,  No.  1 


JUNE,  1904 


UNIVERSITY  Of  fj.L 

22  MAY  191 


THE  INFLUENCE  OF  EARLY  AND  LATE  SPRING 
PLOWING  UPON  CORN  PRODUCTION 

MODESTO  QUIROGA 


(Presented  as  a  graduating  thesis  for  the  Degree  of  Bachelor  of  Science 
Agriculture,  Ohio  State  University,  June,  1904.) 


PUBLISHED  BY  THE  OHIO  STATE  UNIVERSITY 

Entered  as  second-class  matter  at  the  postoffice, 
Columbus,  Ohio. 


TcoA 


THE  INFLUENCE  OF  EARLY  AND  LATE  SPRING 
PLOWING  UPON  CORN  PRODUCTION. 


MODESTO  QUIROGA. 


The  subject  of  soil  fertility  and  the  process  of  setting  free  plant 

ffood  have  received  a  great  amount  of  attention  among  agricultural 
scientists  during  the  last  few  years,  and  it  was  with  the  hope  of  deter- 
5  mining  something  of  the  effect  of  early  and  late  spring  plowing  upon 
3  soil  processes  as  shown  by  crop  production  that  this  investigation 
*  was  begun.  The  object  was  to  study  by  actual  experiment  the  influ- 
-  ence  of  early  and  late  spring  plowing  upon  corn  production  and  to 
—  determine  if  possible  the  causes  of  such  differences  as  might  be  found 
^  to  exist. 

The  experiments  were  conducted  on  the  University  farm,  the 
area  concerned  including  about  three  acres  of  the  large  tract  of  allu¬ 
vial  soil  lying  along  the  Olentangy  river.  The  soil  is  characteristi¬ 
cally  alluvial  in  nature  and  forms  the  first  bottom  lowland  of  the  area 
now  under  cultivation.  The  level  character  of  the  land  avoids  serious 
^3  washing  when  overflows  occur,  the  average  depth  is  about  six  feet, 
and  the  whole  is  underlaid  at  various  depths  by  a  bed  of  gravelly 
£hbsoil  which  insures  natural  drainage.  Mr.  C.  B.  Hoover,  in  his 
“Soil  Types  of  the  Ohio  State  University  Farm,”  classifies  this  soil 
under  the  head  of  “silt  loam”  and  states  that  “from  an  agricultural 
standpoint  this  is  by  far  the  most  important  land  of  the  farm.  It  is 
all  underlaid  by  gravel  at  depths  varying  from  four  to  ten  feet  and  is 
£3  thus  naturally  well  drained.”  The  mechanical  analyses  here  recorded 
fully  confirm  Mr.  Hoover’s  classification.  Two  analyses  were  made, 
the  method  followed  being  similar  to  that  used  in  the  laboratories  of 
the  Bureau  of  Soils.  Analysis  No.  1  was  from  a  composite  of  three 
,,  samples  of  the  surface  foot,  one  from  each  of  the  early  plowed  plots 
A,  C  and  E  (see  diagram),  and  analysis  No.  2  was  from  a  composite 
■  of  three  samples  of  the  surface  foot  of  plots  B,  D  and  F. 

3 


I 


The  following  table  gives  the  results  of  the  analyses,  calculated 
on  the  basis  of  five  gram  samples : 

MECHANICAL  ANALYSIS  OF  SILT  LOAM  SOIL. 


Conventional  Names.  Alys.  No.  1.  Alys.  No.  2. 


Volatile  matter . 

.  .  .  6 

per  cent. 

5 

per 

cent. 

Gravel  (above  2  mm.  dia.) . 

.  .  .  0 

ii 

a 

0.2 

a 

u 

Fine  gravel  (2  to  1  mm.) . . 

.  .  .  0 

ii 

a 

0.3 

a 

u 

Coarse  sand  (1  to  .5  mm.) . 

. .  .  0.2 

a 

a 

0.2 

it 

a 

Medium  sand  (.5  to  .25  mm.) .  . . 

. .  .  0.4 

a 

a 

1.2 

ft 

It 

Fine  sand  (.25  to  .1  mm.) . 

. .  .  4. 

ii 

a 

5.2 

u 

it 

Very  fine  sand  (.1  to  .05) . 

. .  .  14.2 

a 

a 

14.4 

a 

ti 

Silt  (0.05  to  .005) . 

...  60. 

ii 

a 

56. 

a 

(> 

Clay  (0.005  to  .0001) . 

.  .  .  15. 

ii 

a 

15.8 

tt 

it 

Total . 

. .  .  99.8 

98.3 

ARRANGEMENTS  OF  PLOTS. 

The  study  has  covered  six  field  plots  and  has  been  made  to  cover 
the  first,  second  and  third  foot  in  depth,  separately  in  each  case.  The 
following  sketch  of  the  field  gives  a  clear  idea  of  the  arrangement : 


PLOT  °  F  WEST 

PLOT  O  F  EAST 

O 

rn 

1  ; 

NO 

a  o  e 

..  °  D  '•  J 

1  ©  D 

0 

»  o  c  „  “ 

D 

U  O  c  »» 

¥ 

..  OB**  £ 

A 

i  "  °  z 

|or> 

< 

O 

- - - -  — - - 

"  O  A 

40  RODS 

plots  a,c  ,e  early  plo^eo 

*  B.  D  r  LATE 

O  -  APPRO  X  .  PLACE  OF  S/srvt  P  l-i  IM  o 

From  this  sketch  it  will  be  seen:  First,  that  the  experiment 
field  was  divided  into  two  main  portions — stalked  and  unstalked — 
east  and  west  respectively,  aggregating  one  and  a  half  acres  in  each 
portion.  Second,  that  the  six  plots  making  up  the  field  are  called 

A,  B,  C,  D,  E  and  F.  A,  C  and  E  stand  for  early  plowed  land,  and 

B,  D  and  F  for  late  plowed  land.  Each  plot  extends  over  the  whole 
field — stalked  and  unstalked— and  covers  half  an  acre.  W  stands 
for  west  and  E  for  east.  Third,  the  line  of  naughts  shows  approxi¬ 
mately  the  place  of  sampling  throughout  the  season. 

All  tables  and  charts  and  different  combinations  of  results  re¬ 
corded  are  made  out  on  the  same  plan  as  the  sketch,  thus  requiring 
that  they  be  read  in  accordance  with  the  principles  and  indications 
represented  in  the  same. 


4 


PREVIOUS  PREPARATION  OF  THE  GROUND. 

The  land  had  been  cropped  in  rotation  for  several  years.  In 
1900  the  held  was  in  a  timothy  and  clover  meadow.  Previous  to 
that  year  there  had  been  a  crop  of  wheat  taken  off.  For  a  number 
of  years  before  the  wheat  crop,  the  held  had  been  used  by  a  seed  firm 
for  the  growing  of  tomatoes  and  had  been  heavily  manured  during 
that  time,  but  no  manure  has  been  applied  since.  In  1902  it  was 
turned  into  a  corn-held.  At  the  time  of  harvest  the  ears  were  strip¬ 
ped  and  part  of  the  stalks  left  standing  in  the  held. 


WORKING  THE  GROUND,  SEEDING  AND  CULTIVATION. 

On  April  2,  1903,  the  land  was  rolled  and  disked  to  get  the  corn 
stalks  in  order,  so  that  it  could  be  plowed  under.  On  April  7,  the 
early  plots  A  and  C  were  plowed  with  an  Oliver  Chilled  breaking 
plow  to  a  depth  of  five  inches.  On  account  of  rain  the  other  early 
plot  (E)  was  not  plowed  until  April  10.  Then  the  plowed  land  was 
dragged  with  a  plank  drag  and  left  standing  in  that  condition  until 
April  22,  when  it  was  harrowed  with  a  drag  harrow.  It  was  then  left 
until  the  date  of  preparation  of  the  plots  for  seeding.  On  June  3, 
the  late  plots  B,  D  and  F  were  plowed.  Then  the  whole  held  was 
disked  with  a  rolling  cutter  harrow,  worked  with  a  spring-tooth 
harrow,  and  finally  rolled  with  a  tubular  roller.  On  June  4,  the  corn 
was  drilled  with  a  two-horse  planter. 

The  corn  was  cultivated  three  times  during  the  season,  once 
in  June  and  twice  in  July.  The  work  of  cultivation  was  carried 
out  as  follows :  First,  the  drag-tooth  harrow  was  used ;  second, 
the  two-horse  riding  cultivator,  and  third,  the  two-horse  walking 
cultivator  of  the  Malta  make.  The  average  depth  of  this  cultivation 
was  from  two  to  three  inches,  supposed  to  make  a  level  cultivation. 
Weeds  were  cut  out  with  hoes  on  July  25,  26  and  27.  With  the 
exception  of  the  time  of  plowing,  the  plots — early  and  late — were 
treated  practically  alike,  being  plowed  at  the  same  depth,  ground 
prepared  in  the  same  manner  for  planting,  planted  at  the  same  time 
and  cultivated  in  the  same  way  and  as  near  the  same  time  as  possible. 

The  work  of  the  season  has  covered  four  different  lines  of  study ; 
first,  soil  moisture,  second,  variation  of  nitrates,  third,  temperature  of 
the  soil,  and  fourth,  crop.  All  of  them  have  been  referred  to  the 
main  statement,  that  is  to  “The  Influence  of  Early  and  Late  Plowing 
Upon  Corn  Production.” 

I.  SOIL  MOISTURE  AS  INFLUENCED  BY  EARLY  AND  LATE 

SPRING  PLOWING. 

The  importance  of  soil  moisture  in  corn  growing  being  so  well 
recognized,  a  careful  study  of  the  moisture  conditions  throughout  the 
season  was  made  and  results  tabulated,  to  note  the  relation  between 
moisture  content  of  the  soil  and  the  crop  yield. 

5 


TABLE  I. 

SHOWING  THE  ACTUAL  PER  CENT.  OF  MOISTURE  OF  EACH  SAMPLE  TAKEN 
FROM  EARLY  AND  LATE  PLOWED  LAND. 


EARLY  PLOWED 

PLOTS. 

LATE 

PLOWED  PLOTS 

V 

A 

C 

E 

B 

D 

F 

1903 

js 

a 

<l> 

Q 

East 

West 

East 

West 

East 

West 

East 

West 

East 

West 

East 

We 

April  6  .... 

....  I 

35.87 

25.71 

15.63 

29.80 

30.15 

28.17 

28.61 

23.30 

28.43 

24.09 

28.12 

23.: 

“  6  . 

....  II 

26.12 

23.06 

26.66 

11.10 

27.86 

21.74 

25.33 

20.97 

26.16 

19.59 

26.55 

24. 

“  6 . 

....  Ill 

22.50 

16.96 

11.16 

18.21 

26.18 

18.75 

21.73 

21.95 

24.86 

19.37 

24.88 

25. 

“  17  . 

....  I 

29.14 

23.17 

27.44 

29.22 

29.76 

29.46 

21.07 

28.80 

32.44 

28.83 

22.06 

25.^ 

“  17  . 

25.82 

22.43 

24.27 

12.73 

27.57 

25.18 

26.38 

22.50 

26.61 

25.41 

17.44 

24.! 

“  17 . 

....  Ill 

23.55 

23.64 

24.95 

21.02 

25.05 

20.37 

17.17 

17.63 

24.37 

19.91 

23.40 

24.: 

“  20  . 

....  I 

26.00 

26.20 

28.10 

26.14 

24.88 

29.11 

26.62 

25.03 

26.02 

25.63 

24.60 

28.1 

“  20  . 

....  II 

24.78 

23.73 

25.16 

24.18 

27.41 

23.16 

25.88 

24.97 

24.26 

22.41 

27.15 

23. ( 

“  20 . 

....  Ill 

22.95 

23.27 

26.95 

22.53 

24.89 

19.89 

12.68 

22.18 

25.28 

21.58 

23.96 

22. i 

“  27  . 

....  I 

30.78 

23.37 

30.67 

27.50 

28.96 

26.73 

30.41 

25.06 

29.74 

15.35 

27.28 

26. ( 

“  27  . 

....  II 

23.98 

21.82 

26.50 

19.32 

25.20 

23.31 

24.39 

23.65 

25.75 

21.77 

21.61 

22.' 

“  27  . 

....  Ill 

21.78 

20.90 

26.72 

16.82 

25.07 

20.07 

24.55 

23.27 

24.36 

20.57 

22.82 

18. ( 

May  4  . 

....  I 

25.87 

22.31 

25.95 

24.03 

27.37 

25.83 

25.72 

21.84 

23.20 

21.48 

22.59 

14.' 

“  4  . 

....  II 

25.08 

21.37 

26.35 

25.44 

26.40 

22.98 

22.55 

18.48 

25.10 

20.56 

24.65 

23. ( 

“  4  . 

...  Ill 

22.26 

22.54 

25.03 

22.44 

24.79 

19.19 

23.28 

23.47 

24.18 

20.67 

24.27 

14. 1 

“  11  . 

....  I 

24.25 

20.40 

24.77 

18.66 

24.76 

15.37 

25.67 

19.89 

23.63 

16.37 

20.05 

19.' 

“  11  . 

....  II 

23.30 

17.27 

24.59 

22.83 

26.63 

21.63 

25.33 

18.28 

19.36 

21.22 

20.98 

20.! 

“  11  . 

...  Ill 

23.14 

23.66 

30.13 

22.96 

22.02 

- 18.37 

21.95 

21.67 

23.48 

19.91 

25.09 

18.' 

“  19  . 

....  I 

27.27 

21.74 

21.77 

22.72 

21.97 

22.51 

20.46 

14.41 

12.46 

15.25 

19.12 

14. ( 

“  19  . 

....  II 

22.99 

20.57 

23.03 

23.75 

26.17 

23.27 

24.01 

16.31 

17.93 

20.74 

20.81 

22.7 

“  19 . 

...  Ill 

23.55 

21.07 

27.33 

21.22 

24.56 

19.71 

23.25 

22.22 

23.86 

19.50 

25.42 

22.! 

“  27  . 

....  I 

23.60 

22.32 

21.71 

9.77 

25.83 

22.10 

21.87 

21.70 

17.35 

18.78 

19.04 

18.7 

“  27  ..... 

....  II 

21.39 

21.70 

21.20 

20.92 

24.64 

20.15 

24.51 

20.09 

15.31 

17.86 

17.77 

18.! 

“  27 . 

...  Ill 

17.02 

23.21 

21.55 

19.05 

24.71 

18.11 

22.07 

21.09 

17.46 

19.16 

22.04 

13.; 

June  3  . 

....  I 

41.31 

23.37 

26.72 

23.76 

27.60 

26.91 

25.59 

18.18 

21.68 

21.77 

19.47 

23.' 

-  . 

...  II 

26.13 

19.36 

23.55 

24.48 

26.14 

22.29 

23.79 

16.74 

17.42 

20.32 

17.16 

20. ( 

“  3  . 

...  Ill 

20.70 

20.07 

25.48 

21.77 

24.50 

11.77 

23.29 

17.95 

23.61 

19.60 

22.65 

16.J 

“  13  . 

....  i 

28.98 

23.98 

27.25 

27.87 

26.22 

27.47 

27.35 

24.50 

28.48 

20.79 

27.09 

26.! 

“  13  . 

....  II 

25.38 

22.85 

24.87 

23.74 

28.11 

23.37 

25.32 

21.52 

24.82 

23.73 

25.08 

30. ( 

"  13  . 

...  Ill 

21.46 

23.57 

25.43 

22.76 

18.85 

18.69 

22.74 

16.93 

24.57 

21.34 

23.90 

18.1 

“  19  . 

....  I 

26.14 

22.59 

26.68 

26.78 

26.45 

25.46 

26.03 

25.28 

25.36 

23.60 

27.33 

25.1 

“  19  . . 

....  II 

24.47 

22.95 

27.62 

25.27 

26.33 

23.27 

25.22 

24.03 

25.63 

22.87 

24.75 

21.2 

“  19  . 

23.36 

24.31 

25.31 

23.96 

26.25 

18.65 

23.10 

23.56 

26.83 

20.37 

24.72 

16. t 

July  1  . 

34.72 

27.27 

25.03 

25.86 

26.23 

16.18 

24.60 

28.41 

24.27 

21.78 

22.27 

22.4 

“  1  . 

....  II 

24.52 

18.91 

26.84 

25.55 

27.24 

28.31 

24.86 

25.77 

23.84 

22.75 

23.08 

24  4 

“  1  . 

...  Ill 

22.73 

23.22 

26.54 

21.17 

26.36 

21.50 

22.69 

22.43 

24.51 

19.09 

25.53 

22.4 

8  . 

....  I 

25.77 

17.06 

25.85 

21.18 

26.48 

24.73 

27.85 

25.49 

23.06 

21.16 

24.03 

21.8 

,f  8  . 

23.78 

23.00 

25.00 

20.97 

25.00 

22.68 

27.12 

22.11 

23.42 

19.97 

22.26 

19.6 

“  8  . 

...  Ill 

21.07 

23.83 

22.59 

20.37 

20.75 

10.25 

24.10 

26.20 

22.50 

18.63 

24.11 

18.4 

“  14  . 

....  I 

14.42 

23.09 

25.87 

22.37 

23.79 

27.38 

25.60 

24.60 

20.83 

18.61 

31.73 

24  7 

“  14  . 

...  II 

21.71 

21.86 

24.25 

22.30 

21.10 

22.37 

24.33 

23.40 

21.92 

19.56 

19.33 

19.2 

“  14  . 

...  Ill 

21.03 

24.54 

21.56 

20.72 

22.37 

16.94 

17.51 

19.11 

23.18 

18.71 

15.25 

18.6 

“  21  . 

.  I 

17.28 

13.92 

18.74 

16.94 

13.90 

14.07 

18.39 

17.37 

21.16 

17.65 

17.80 

16.6 

“  21  . 

19.08 

17.87 

20.26 

11.65 

16.46 

13.69 

24.27 

18.82 

24.65 

15.89 

22.66 

17.5 

“  21  . 

...  Ill 

23.28 

21.96 

22.80 

19.26 

23.25 

17.39 

17.36 

21.10 

26.39 

20.55 

12.98 

16.8 

“  28  . . 

....  I 

15.00 

16.40 

16.19 

15.65 

12.34 

15.76 

17.89 

16.73 

16.32 

14.97 

16.75 

17.9 

“  28  . 

...  II 

22.62 

17.43 

20.94 

16.31 

24.82 

16.77 

22.51 

18.81 

17.35 

17.18 

21.79 

15.3 

“  28 . 

...  Ill 

22.97 

16.95 

21.29 

16.90 

23.40 

15.55 

22.91 

20.55 

21.28 

17.32 

25.20 

18.2 

Aug.  4  . 

15.55 

15.75 

15.78 

14.20 

17.29 

17.18 

15.37 

13.48 

13.21 

14.64 

23.91 

15.0 

“  4  . 

20.49 

22.90 

20.81 

20.35 

35.09 

21.11 

16.09 

17.97 

18.81 

19.02 

23.40 

15.4 

“  4  . 

19.62 

23.01 

20.73 

12.30 

22.05 

22.35 

20.61 

21.37 

20.84 

20.27 

23.20 

20.9 

“  11  . 

16.01 

14.21 

18.14 

16.98 

16.11 

17.53 

16.37 

16.76 

17.24 

15.48 

19.51 

14  0 

“  11  . 

...  II 

19.38 

17.33 

22.16 

18.66 

19.75 

18.01 

20.53 

17.11 

20.95 

17.07 

19.30 

18  0 

"  11  . 

20.05 

18.76 

24.75 

17.45 

21.75 

15.80 

19.59 

19.43 

22.05 

17.05 

22.15 

18.1 

“  18  . 

7.11 

9.48 

16.33 

12.87 

15.77 

16.14 

14.59 

16.19 

15.32 

22.20 

17.39 

6.1! 

“  18  . 

16.93 

15.47 

17.96 

29.70 

24.34 

15.03 

17.40 

13.40 

18.17 

21.55 

18.54 

16.0: 

“  18 . 

28.06 

16.52 

21.23 

14.38 

20.45 

17.36 

17.54 

15.38 

15.34 

12.67 

19.37 

12.9 

“  25  . 

'  13.62 

13.86 

15.62 

14.08 

16.26 

10.93 

15.20 

14.93 

9.00 

16.33 

18.33 

16.1' 

“  25  . 

17.71 

17.12 

19.39 

17.66 

16.30 

20.04 

17.78 

15.40 

16.70 

15.38 

18.36 

17.3’, 

25  ...... 

15.62 

16.66 

15.73 

16.52 

17.75 

17.50 

14.21 

16.12 

17.28 

15.47 

17.26 

17. 7( 

Sept.  1  . 

9.86 

13.05 

11.54 

15.67 

13.91 

13.97 

9.81 

14.05 

9.04 

14.20 

14.21 

12.4! 

“  1  . 

17.24 

16.72 

13.15 

17.24 

17.07 

14.71 

17.15 

17.02 

23.04 

16.58 

16.69 

18.3! 

“  1  . 

15.14 

15.80 

16.93 

15.76 

21.68 

14.29 

14.25 

15/48 

15.96 

18.31 

17.02 

14.97 

“  8  . 

14.16 

12.91 

15.21 

11.31 

13.95 

13.02 

14.61 

11.56 

10.04 

7.56 

14.39 

9.2( 

“  8  . 

15.82 

15.43 

17.82 

12.14 

18.31 

14.23 

19.55 

16.18 

10.99 

15.89 

15.28 

13.1! 

“  8 . 

16.15 

13.78 

16.36 

15.11 

17.33 

14.18 

16.71 

12.20 

14.96 

11.44 

13.05 

16.2! 

“  15  . 

15.69 

15.16 

15.62 

19.79 

24.75 

16.22 

15.60 

17.41 

15.87 

15.30 

14.84 

12.7 

“  15  . 

18.49 

18.54 

16.60 

18.79 

21.30 

16.76 

18.24 

17.83 

20.43 

16.78 

15.13 

16.4* 

“  15  . . 

...  Ill 

13.42 

16.38 

14.18 

17.27 

18.32 

14.43 

14.72 

17.19 

16.64 

13.32 

17.42 

11.91 

“  22  . 

18.44 

20.07 

18.80 

21.95 

25.77 

19.71 

13.40 

18.77 

17.64 

16.81 

21.85 

18.W 

“  22  . 

19.53 

19.00 

20.12 

17.73 

28.50 

17.21 

19.10 

17.76 

19.07 

15.75 

19.35 

16. 5( 

“  22 . 

17.06 

16.71 

14.35 

17.46 

18.72 

13.04 

19.17 

16.90 

17.87 

12.67 

18.19 

i4. a 

“  29  . 

15.10 

18.20 

16.64 

18.78 

16.49 

17.09 

20.19 

17.21 

16.57 

16.49 

18.63 

16. 1( 

“  29  . 

18.11 

19.06 

19.43 

18.44 

20.42 

17.92 

18.70 

16.56 

19.46 

18.93 

18.66 

16.4! 

“  29 . 

17.38 

16.80 

19.07 

15.74 

18.12 

13.13 

17.08 

14.19 

18.23 

12.79 

17.19 

15. 0C^ 

6 


The  season  of  1903  was  extremely  dry  and  hot,  with  only  13.36 
inches  of  rainfall  from  April  1  to  September  30.  The  rainfall  for 
April  and  May,  the  time  before  seeding,  was  5.27  inches,  that  is,  .32 
inch  less  than  that  recorded  for  the  months  of  July,  August  and 
September  together,  which  only  amounted  to  4.95  inches.  The 
precipitation  for  June,  the  time  of  planting,  was  3.14  inches,  which 
together  with  that  for  the  last  three  months  makes  a  total  of  8.09 
inches  of  rainfall  for  the  growing  season  of  our  experiment.  The 
dryest  month  of  the  season  was  August,  with  only  .63  inch  of  rain, 
.22  inch  being  the  highest  single  rain  record  for  the  month. 

METHODS  OF  WORK. 

The  soil  moisture  for  the  growing  season  is  given  in  three  tables 
and  one  chart.  The  study  covered  900  samples  taken  from  the  early 
and  late  plowed  plots  at  the  depths  of.  one,  two  and  three  feet. 
Duplicate  samples  were  taken  each  time,  thus  making  a  total  of  36 
separate  samples  for  each  date.  (See  sketch  of  field.)  The 
process  of  sampling  was  carried  out  as  follows :  A  tube  seven- 
eighths  inch  in  diameter,  four  feet  long  and  bearing  footmarks,  was 
driven  into  the  ground  to  the  depth  of  one,  two  and  three  feet.  The 
soil  was  emptied  into  tin  boxes,  and  the  lid  screwed  on  to  prevent 
waste  of  soil  and  loss  of  moisture  by  evaporation.  In  the  laboratory 
they  were  weighed,  the  lids  taken  off  and  then  placed  in  an  oven  at  a 
temperature  of  110°  C.,  where  they  were  left  until  a  constant  weight 
was  obtained.  The  actual  per  cent,  of  moisture  content  was  calculated 
to  the  dry  weight  of  each  sample.  Table  I  contains  these  results. 

The  seasonal  average  per  cent,  of  moisture  for  the  surface-foot 
for  each  separate  plQt  is  given  below: 


Plots 

East  Sec. 

Seasonal  Average 

West  Sec. 

Average 

Early.  . 

.A 

18.07 

19.50 

18.78 

C 

21.28 

16.55 

18.91 

E 

23.77 

21.04 

22.40 

Late .  . . 

.B 

21.03 

16.09 

18.56 

D 

15.96 

18.60 

17.28 

F 

21.29 

19.16 

20.22 

The  actual  per  cent,  of  moisture  in  the  second  foot  recorded 
for  each  sample  is  decidedly  uniform  in  a  large  number^  of  instances. 
One  hundred  and  seventy-four  samples  were  found  to  have  a  moist¬ 
ure  content  ranging  between  20  and  30  per  cent.,  and  in  126  samples 
the  per  cent,  was  below  20,  the  minimum  being  10.99  per  cent.  Of 
the  174  samples,  98  were  taken  from  the  early  plowed  land.  The 
seasonal  average  per  cent,  of  moisture  of  the  second  foot  samples 
taken  from  each  plot  is  as  follows : 

7 


Plots 

Early .  . 

.A 

East  Sec. 

22.19 

Seasonal  Average 

West  Sec. 

20.39 

Average 

21.29 

C 

22.34 

20.08 

21.21 

E 

20.73 

20.36 

20.59 

Late . . . 

.B 

22.41 

19.43 

20.92 

D 

20.57 

19.47 

20.02 

F 

20.13 

19.94 

20.33 

In  the  third  foot  set  of  samples  there  were  found  155  with  an 
actual  per  cent,  of  moisture  ranging  between  20  and  30  per  cent., 
and  145  which  dropped  below  20  per  cent.  In  the  samples  taken 
from  April  6  to  August  18,  there  were  found  155  with  more  than  20 
per  cent,  of  moisture.  Of  these,  83  came  from  the  early  and  72  from 
the  late-plowed  land.  From  August  18  to  September  29,  all  third 
foot  samples  were  found  to  have  a.  water  content  lower  than  20  per 
cent.  The  seasonal  average  per  cent,  of  moisture  of  each  plot  for 
the  third  foot  is  as  follows : 


Plots 

East  Sec. 

Seasonal  Average 

West  Sec. 

Average 

Early.  . 

.A 

20.64 

20.32 

20.48 

C 

21.92 

18.92 

20.42 

E 

22.37 

17.45 

19.81 

Late .  . . 

.B 

19.79 

19.58 

19.68 

D 

21.59 

18.01 

19.80 

F 

21.24 

18.80 

20.02 

The  seasonal  average  per  cent,  of  moisture  of  the  surface  two 
feet  for  each  plot  is  as  follows : 

Early  plowed  plots . A,  20.03  C,  20.06  E,  21.49 

Late  “  “  . B,  19.74  D,  18.65  F,  20.27 

Surface  three  feet  seasonal  average  per  cent,  of  moisture  by 
plots : 

Early  plowed  plots . A,  20.18  C,  20.18  E,  20.93 

Late  “  “  . B,  19.38  D,  19.03  F,  20.19 

Table  II.  Table  II  is  one  of  averages  for  each  date  of  sampling. 
From  the  column  “General  Averages”  of  this  table,  Chart  I  was 
made. 

Chart  I.  From  this  chart  it  will  be  seen  that  the  per  cent,  of 
moisture  on  the  25  dates  of  sampling  is  higher  in  18  cases  of  the 
surface-foot,  19  of  the  second  foot  and  18  of  the  third  foot  for  the 
early  plowed  land.  There  is  recorded  for  the  surface  foot,  a  moisture 
content  above  20  per  cent,  for  early  and  late-plowed  land  from 
April  6  to  July  14,  with  the  exception  of  two  samples  taken  from  the 

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9 


TABLE  II. 

SHOWING  AVERAGE  PER  CENT.  OF  MOISTURE  BY  FEET  AND  BY  PLOTS  FOR  EACH  DATE  OF  SAMPLING. 


GENERAL  AVERAGE  PERCENT  OF  MOISTURE  BY  FEET  FOR  EACH  DATE  OF  SAMPLING 


10 


late-plowed  plots,  on  May  19  and  27.  Between  these  same  dates,  it 
is  to  be  noticed  that  the  per  cent.,  whether  above  or  below  20,  is 
higher  for  the  early  than  for  the  late-plowed  plots,  with  the  exception 
of  the  samples  taken  on  July  8  and  14. 

The  average  per  cent,  is  below  20  from  July  21  to  the  end  of  the 
season,  with  the  exception  of  September  22.  The  moisture  content 
is  higher  from  July  8  to  August  18  for  the  late-plowed  plots,  with  the 
exception  of  August  4.  The  fact  that  the  per  cent,  for  the  late- 
plowed  plots  was  higher  than  that  for  the  early  between  the  dates  of 
July  8  and  August  18,  is  partly  explained  by  the  results  obtained 
for  the  second  foot  for  the  same  period,  which  show  a  higher  per 
cent,  for  the  early-plowed  plots,  with  the  exception  of  July  21.  From 
August  25  to  September  22  the  per  cent,  of  moisture  content  for  the 
surface-foot  is  also  in  favor  of  the  early-plowed  plots 

In  the  second  foot,  with  the  exception  of  the  samples  taken  on 
April  6,  17  and  20,  June  13  and  September  1,  the  average  per  cent, 
of  moisture  content  is  decidedly  in  favor  of  the  early-plowed  land. 

The  third  foot  shows  more  variation  in  its  moisture  content  in 
favor  of  the  late-plowed  land  than  was  the  case  with  the  first  and 
second  foot.  On  seven  different  dates  the  per  cent,  of  water  of  the 
early-plowed  land  failed  to  rise  above  that  of  the  late  plowed,  but  it 
should  be  observed  that  on  the  same  dates  there  is  a  more  or  less  well 
noted  difference  in  favor  of  the  early  plowed,  either  in  the  surface  or 
in  the  second  foot,  or  in  both  simultaneously. 

II.  AVAILABLE  SOIL  NITROGEN  AS  INFLUENCED  BY 
EARLY  AND  LATE  PLOWING. 

Side  by  side  with  the  moisture  determinations,  a  study  was  made 
of  the  available  nitrogen  in  the  soil  throughout  the  season.  The 
determinations  were  made  for  one,  two  and  three  feet  in  depth  sepa¬ 
rately  from  four  sets  of  samples,  two  from  the  early  and  two  from 
the  late-plowed  land.  Of  the  early  and  late  one  each  was  taken  from 
the  east  and  west  sections  respectively.  The  investigation  covered, 
first,  the  study  of  samples  taken  before  plowing  on  April  6 ;  second, 
the  study  of  samples  collected  the  day  before  seeding  on  June  3; 
third,  the  study  of  samples  taken  on  different  dates  during  the  grow¬ 
ing  season  from  June  13  to  September  29.  The  amounts  of  nitrogen 
found  in  the  soil  have  been  recorded  at  each  interval  and  for  each 
depth.  The  data  have  been  derived  from  more  than  600  cores  of 
soil,  each  one  foot  long. 

DETERMINATION  OF  NITRATES  AS  NITROGENTN  THE|SOIL. 

When  the  moisture  had  been  determined,  the  several  cores  of  a 
sample  were  ground  up  as  fine  as  practicable  and  thoroughly  mixed, 
and  from  this  mixed  composite  the  samples  for  the  nitrogen  deter¬ 
mination  were  taken.  The  Chemo-Colorimetric  method,  used  in  the 
examination  of  water  for  sanitary  and  technical  purposes,  was  foi- 

11 


lowed.  The  soil  solution  was  prepared  after  a  modification  of  King’s 
method,  which  is  as  follows :  Take  50  grams  of  the  mixed  composite, 
place  in  a  clean,  linen  bag  and  pour  over  it  in  a  mortar  250  cc.  of  a 
one  per  cent,  solution  of  formaldehyde  made  up  of  244  cc.  of  distilled 
water,  5.36  cc.  of  a  saturated  solution  of  potassium  alum  crystals  and 
0.64  cc.  of  commercial  formalin.  Knead  the  soil  with  a  pestle  for 
two  and  one-half  minutes,  at  the  same  time  constantly  turning  the 
bag.  Wring  the  bag  out  as  dry  as  possible,  pour  the  soil-water- 
solution  into  a  glass  jar,  and  set  it  away  to  clear.  Measure  25  cc.  of 
the  clear  solution  into  a  clean  porcelain  dish  by  means  of  a  pipette 
and  evaporate  to  dryness  on  a  steam  bath.  When  dry,  add  1  cc.  of 
disulphonic  acid  prepared  after  the  method  of  Leffmann  and  Beam 
(take  37  cc.,  strong  sulphuric  acid,  3  cc.  water,  6  grams  of  phenol. 
Boil  in,  not  on,  a  water  bath  for  at  least  six  hours,  etc.),  and  work 
thoroughly  over  the  surface  until  residue  has  dissolved.  After  10 
minutes,  including  the  time  of  working  the  sample,  add  20  cc.  of 
distilled  water  and  enough  ammonium  hydroxide  to  make  the  solu¬ 
tion  alkaline,  using  litmus  paper  for  indicator.  Rinse  the  solution 
into  a  Nessler  tube  and  compare  with  a  standard  of  known  strength. 
The  standard  is  prepared  from  chemically  pure  KNOa  after  the 
method  of  Leffmann  and  Beam.  Take  “0.722  grams  of  KN03  pre¬ 
viously  heated  to  a  temperature  just  sufficient  to  fuse  it,  dissolve  in 
water  and  make  up  the  solution  to  1000  cc. ;  1  cc.  of  this  solution 
will  contain  0.0001  gram  of  nitrogen.”  From  10  cc.  of  this  make  a 
solution  in  distilled  water,  1  cc.  of  which  will  contain  0.00001  gram 
of  nitrogen.  When  a  color  standard  is  desired  10  cc.  of  this  solution 
is  treated  in  the  same  way  as  a  solution  from  a  soil  sample.  An 
aliquot  of  the  color  solution  is  diluted  until  it  contains  0.0000005 
gram  of  nitrogen  to  every  cc.  Calculate  results  in  part  per  million 
of  the  dry  weight  of  sample. 

The  alum  flocculates  the  sediment  and  gives  a  clear  solution 
quickly.  The  formalin  prevents  changes  in  nitrates,  but  it  is  always 
advisable  to  allow  the  solution  from  each  sample  to  stand  the  same 
length  of  time  while  clearing,  for  instance  five  to  six  hours.  Not¬ 
withstanding  the  action  of  the  formalin  the  nitrates  in  a  soil  sample 
are  liable  to  change  if  left  standing  for  some  time. 

Table  III.  In  this  table  there  is  given  the  actual  amount  of 
nitrogen  as  found  on  each  date  of  sampling  by  the  method  described 
above.  The  data  have  been  combined  so  as  to  show  the  mean 
amounts  of  nitrogen  in  each  section  of  the  field — east  and  west — 
both  for  early  and  late-plowed  land,  for  each  month  and  for  the 
season.  The  analysis  of  samples  taken  before  plowing,  April  6,  for 
second  foot,  surface-two  and  surface-three  feet  show  a  larger  amount 
of  nitrogen  for  the  late  than  for  the  early-plowed  plots.  It  should 
be  observed  that  the  nitrogen  recorded  for  the  second  foot  at  the 
same  time  in  the  east  late-plowed  plot  is  42  parts  per  million  of  dry 
soil.  This  amount  is  by  far  greater  than  that  found  on  any  date  and 
at  any  depth  throughout  the  season.  This  was  supposed  to  be  an 

12 


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13 


SHOWING  ACTUAL  AVAILABLE  NITROGEN  IN  PARTS  PER  MILLION  OF  DRY  SOIL  IN  EARLY  AND  LATE  PLOWED  LAND. 


error  and  a  new  sample  was  worked  over  three  times  which  gave 
practically  the  same  results  in  each  instance.  A  probable  explanation 
of  this  fact  is  the  presence  of  a  soluble  nitrogenous  deposit  of  some 
kind  in  that  particular  place.  It  could  not  have  been  the  result  of 
nitrification  because,  there  being  favorable  conditions  for  the  work 
of  bacteria  throughout  the  season,  the  effects  of  the  latter  would 
have  been  shown  for  the  plot  on  subsequent  dates,  more  or  less  in 
the  same  proportional  rate,  as  was  found  for  the  remaining  plots  of 
the  field.  It  could  not  have  been  due  to  an  increase  of  temperature 
above  110°  C.  while  drying,  because  all  of  the  samples  were  dried  at 
the  same  time  and  all  would  have  been  affected  alike. 

It  will  also  be  seen  from  the  table  that  216  composite  samples 
were  used.  They  were  taken  from  the  early  and  late-plowed  land 
from  depths  of  one,  two  and  three  feet  separately.  Of  these,  108 
form  the  two  early  sets  from  the  east  and  west  sections  of  the  field. 
The  other  108  form  the  late  sets,  also  from  the  east  and  west  sections. 
Seventy-two  samples  were  taken  from  the  surface-foot,  36  early  and 
36  late.  In  33  instances  out  of  the  early  the  amount  of  available 
nitrogen  throughout  the  season  was  higher  than  that  of  the  late, — 
comparison  being  made  between  samples  from  sets  taken  on  the  same 
date,  comparing  east  with  east  and  west  with  west.  In  the  sets 
taken  on  April  6,  June  13  and  September  15  were  found  the  three 
instances  where  the  available  nitrogen  of  the  early-plowed  land  was 
less  than  that  of  the  late. 

Comparisons  were  made  in  like  manner  for  the  second  and  third 
feet  and  the  amount  of  available  nitrogen  was  found  to  be  greater 
for  the  late-plowed  land  in  only  eight  samples,  four  from  the  second 
and  four  from  the  third  foot.  Thus  it  will  be  seen  that  throughout 
the  entire  season,  there  were  only  11  instances  out  of  the  whole  108 
early  sets  where  the  available  nitrogen  was  greater  for  the  late- 
plowed  land. 

It  will  also  be  noticed  that  at  the  time  of  seeding,  June  3,  the 
nitrogen  of  the  surface-foot  in  the  early-plowed  plots,  east  and 
west,  is  seven  to  nine  times  as  much  as  it  was  at  the  beginning 
of  the  season,  while  with  the  late-plowed  plots  the  nitrogen  has  only 
increased  from  two  to  four  times  as  much.  The  same  rate  of  increase 
is  seen  in  the  nitrogen  found  in  both  early  and  late-plowed  plots,  east 
and  west  sections,  from  June  3  to  July  28,  while  from  August  4  a 
gradual  decrease  is  observed  in  both  fields  until  the  close  of  the 
season.  The  same  is  more  or  less  true  with  the  results  found  in  the 
second  and  third  feet.  But  here  the  nitrogen  present  is  more  than 
one-third  less  than  that  found  in  the  surface-foot,  gradually  decreas¬ 
ing  with  the  depth.  The  monthly  and  seasonal  record  is  a  strong 
confirmation  of  the  same  law  of  development  and  variation  of  avail¬ 
able  nitrogen  throughout  the  season  in  the  early  and  late-plowed 
land.  In  both  fields  the  amount  of  nitrogen  was  highest  in  June  and 
July  at  all  depths.  The  seasonal  general  average  shows  that  the 
amount  of  nitrogen  at  all  depths  is  greater  in  the  early-plowed  plots 
than  in  the  late. 


14 


CHART  II  (rnoM  table  irf) 

GENERAL  AVERAGE  OF  AVAILABLE  NITROGEN  IN  PARTS 
PER  MILLION  OF  DRV  SOIL 


J5 


Chart  II.  It  will  foe  seen  that  the  average  amount  of  nitrogen 
found  in  the  early  plots  is  higher  than  that  recorded  for  the  late- 
plowed  land  in  the  surface  and  third  foot  at  the  beginning  of  the 
season,  while  in  the  second  foot  the  nitrogen  was  in  favor  of  the  late- 
plowed  land.  A  gradual  increase  took  place  in  the  surface-foot,  in 
both  early  and  late  plots,  until  July  21.  From  this  time  there  was  a 
gradual  decrease  of  the  nitrogen  present  in  the  soil  until  the  end  of 
the  season,  the  difference  in  all  cases  being  in  favor  of  the  early- 
plowed  land  over  the  entire  field.  The  same  is  more  or  less  true 
for  the  second  and  third  feet. 

Note.  It  should  be  observed  that  the  record  for  the  second 
foot,  east,  late  plot,  on  April  6  is  given  in  Table  III  as  4.2.  This  is 
one-tenth  of  the  real  amount  of  nitrogen  found  in  the  sample  and 
was  used  for  convenience  in  calculating  the  table  and  making  the 
chart. 

III.  SOIL  TEMPERATURE  AS  INFLUENCED  BY  EARLY 
AND  LATE  PLOWING. 

The  experiment  in  this  line  of  study  covered  separately  the  first, 
second  and  third  feet  in  depth,  the  observations  being  taken  from 
June  6  to  September  22.  The  method  used  in  the  work  was  that 
originated  by  M.  Whitney  and  L.  J.  Briggs  of  the  Bureau  of  Soils  at 
Washington,  D.  C.,  known  as  “The  Electrical  Method  of  Determining 
the  Temperature  of  Soils.”  It  is  described  in  Bulletin  Nos.  6,  7  and 
15  of  the  Bureau  of  Soils,  United  States  Department  of  Agriculture. 

Chart  III  contains  the  results  obtained  throughout  the  season. 
The  soil  temperature  at  which  germination  started  and  the  real 
growth  of  the  corn  began,  as  shown  by  this  chart,  ranges  in  the  sur¬ 
face-foot  between  60.63°  to  66.14°  F.  for  the  early-plowed  land,  and 
between  61.83°  to  67.78°  F.  for  the  late-plowed  plots.  77.68°  and 
79°  F., the  highest  temperatures  throughout  the  season, were  recorded 
on  August  4  for  the  early  and  late-plowed  plots  respectively.  From 
the  table  it  will  also  be  seen  that  the  range  of  temperature  for  each 
foot  during  the  season  is  lower  for  the  early-plowed  land  than  that 
found  for  the  respective  late-plowed  plot. 

It  will  also  be  seen  that  the  temperature  for  the  early-plowed 
plots  falls  below  that  recorded  for  the  late-plowed  land  in  each 
respective  depth  on  nearly  every  date  of  observation.  The  only 
exceptions  to  this  are  June  21  and  September  8  in  the  surface-foot, 
June  6  and  21,  July  8,  August  18  and  25  and  September  1  and  8  in 
the  second  foot,  and  July  8  in  the  third  foot.  A  great  fluctuation  of 
temperature  is  recorded  for  the  second  foot.  The  striking  difference 
between  the  observations  recorded  for  the  surface-foot  on  September 
8  and  for  the  second  foot  on  July  28  is  due,  perhaps,  to  error  in 
reading  the  instrument.  As  a  general  rule,  the  temperature  more  or 
less  gradually  increases  at  all  depths  until  the  last  part  of  July  and 
the  beginning  of  August,  but  from  about  August  4  an  irregular  de¬ 
crease  follows  in  the  first  and  second  feet  until  the  end  of  the  season, 

16 


inches  DEOf?ec6  f*.  ptttftees  p*  decrees. 


CHART  ni 

variation  orsofL  temperature  For  eaply  and  late  plowed  lano 


JUNE  uu  LY'  AUGUST  SEPTEM06R 


i 

3  2. 

a 

J  2 

f  / 

S  2 

S  ... 

P  ' 

5 _  22.  _ 

\ 

/ 

2V 

_ 

/ 

/  > 

\ 

\ 

\ 

\ 

_ 

\  \ 

:\ 

/ 

V 

\  \ 

\  V 

\\ 

y 

CJJRI 

-a  r.  p- 

F~n>C 

)T 

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V 

EARL 

t'  PLO 

WED 

LA  7  i 

L - >1 

BA1WI 

“All-  i 

W  INCH 

(=■«;  fte] 

T  WE1E 

in/  o  Ayq 

nr  (1 

RArp  \y 

k-r  i  O.N 

/ 

/ 

\ 

\ 

/ 

\ 

\ 

/ 

- ^ - 

  ~  - 

\ 

N 

_ 

17 


while  in  the  third  foot  the  increase  goes  on  until  September  1,  and 
is  then  followed  by  a  very  slight  decrease. 

The  mean  soil  temperature  for  each  depth  for  the  season  is  as 
follows :  (Expressed  in  degrees  F.) 


Early  Plowed 
Land. 

Late  Plowed 
Land. 

Difference. 

Surface-foot  . 

.  68.76° 

70.41° 

1.65° 

Second  foot . 

.  66.17° 

66.75° 

0.58° 

Third  foot . 

.  62.79° 

64.42° 

1.63° 

Average  mean  temperature : 

Surface-two  feet . 

.  67.46 

68.58 

1.12 

Surface-three  feet  .... 

.  65.90 

66.52 

0.62 

It  will  be  noticed  that  the  amount  of  moisture  in  the  soil  seemed 
to  be  the  controlling  factor  in  determining  the  temperature ;  that  is  a 
high  moisture  content  as  in  the  early-plowed  plots  caused  a  lower 
temperature  than  that  in  the  less  moist,  late-plowed  plots,  and  this 
influence  was  sufficient  to  overcome  other  factors  working  in  the 
opposite  direction. 

IV.  THE  CROP. 

The  season  of  1903  was  very  dry  and  hot  for  this  region,  with 
only  13.36  inches  of  rainfall  from  April  to  September;  3.14  in  June, 
the  month  of  seeding,  is  the  highest  monthly  record  for  the  season. 
The  rainfall  for  July,  August  and  September  hardly  reached  4.95 
inches ;  consequently  the  crop  suffered  badly  from  drought  during  the 
time  of  growth.  In  the  last  part  of  July,  August  and  September  it 
was  noticed  that  the  leaves  of  many  plants  began  to  curl  early  in  the 
day  and  to  turn  a  yellowish  color.  The  actual  amount  of  moisture 
in  the  soil  at  this  time,  in  many  instances,  as  will  be  seen  from  Table 
I,  failed  in  both  fields — early  and  late  plowed — to  rise  above  12  per 
cent.  In  general,  however,  no  noticeable  differences  were  shown  in 
the  growth  of  the  crop  on  the  different  plots  throughout  the  season. 

On  October  10  the  corn  was  cut  by  hand  and  left  in  the  shock 
until  November  21,  when  it  was  husked.  The  corn  grown  was  a  white 
variety  known  as  Farmers’  Interest,  a  rather  late  variety  for  this 
region,  and  for  that  reason  it  was  not  well  matured  at  the  time  of 
frost. 

The  crop  yield  was  as  follows :  32.71  bushels  per  acre  for  the 

early-plowed  land  against  26  bushels  per  acre  for  the  late-plowed 
land,  which,  makes  a  mean  production  of  29.36  bushels  per  acre. 
The  production  of  fodder  from  the  early-plowed  land  only  exceeded 
that  harvested  from  the  late  plowed  by  32  pounds. 

Table  IV.  This  table  fully  shows  the  crop  yield  in  pounds,  and 
from  it,  it  will  be  seen  that  the  rate  of  increase  of  the  yield  in  favor 
of  the  early  spring  plowed  land  was  455.3  pounds,  or  6.6  bushels  of 
corn  per  acre ;  that  is,  the  gain  would  be  worth  $2.64  per  acre  with 

18 


TABLE  IV. 

CROP  YIELD,  IN  POUNDS. 

Early  Plowed  Plots. 


PRODUCT 

A 

C 

E 

East 

West 

Total 

East 

West 

Total 

East 

West 

Total 

Corn  and  Fodder . 

1922 

2120 

4042 

1533 

1811 

3344 

1785 

2015 

3800 

Corn . 

480 

691 

1171 

480 

475 

955 

600 

611 

1211 

Fodder  . 

1442 

1429 

2871 

1053 

1336 

2389 

1185 

1404 

2589 

Late  Plowed  Plots. 


PRODUCT 

B 

D 

F 

East 

West 

Total 

East 

West 

Total 

East 

West 

Total 

Corn  and  Fodder . 

1708 

1837 

3545 

1591 

1769.5 

3360.5 

1760 

1805 

3565 

Corn . 

440 

435 

875 

400 

441.5 

841.5 

455 

482 

937 

Fodder  . 

1268 

1402 

2670 

1191 

1328 

2519 

1305 

1323 

2628 

Grand  Total. 


PRODUCT 

EARLY  PLOTS 

LATE  PLOTS 

Difference  in 

Favor  of  Early 

Plots 

Corn  and  Fodder . 

11,186 

10,470.5 

715.5 

Corn . 

3,337 

2,653.5 

683.5 

Fodder  . 

7,849 

7,817. 

32. 

Yield  in  Pounds  of  Early  and  Late  Plowed  Land,  as  Affected  by  Stalks. 


PRODUCT 

EAST  PLOTS 
STALKED  LAND 

WEST  PLOTS 
UNSTALKED  LAND 

TOTAL  YIELD 

Difference 
in  Favor 
of 

Early 

Late 

Early 

Late 

Stalked 

Unstalked 

Unstalked 

Land 

Corn  and  F odder .  ■ 

5240 

5059 

5946 

5411.5 

10,299 

11357.5 

1058.5 

Corn . 

1560 

1295 

1777 

1358.5 

2855 

IQA  C 

OidJi  J 

ZoU.D 

Fodder  . 

3680 

3764 

4169 

4053 

7444 

8222 

778. 

19 


corn  at  40  cents  per  bushel.  Comparing  the  crop  production  by 
plots  it  will  be  noticed  that  the  crop — corn  and  fodder — from  the 
early  plot  A  produced  497  pounds  more  than  the  late  plot  B,  681.5 
pounds  more  than  the  late  plot  D,  and  477  pounds  more  than  the 
late  plot  F.  Taking  the  yield  of  corn  alone,  the  difference  in  favor 
of  the  same  plot  A  against  that  of  the  late  plots  was  as  follows: 
295.5  pounds  more  than  B,  329.5  more  than  D,  and  234  pounds  more 
than  F.  The  difference  of  yield  for  corn  and  fodder,  or  for  corn 
alone,  between  the  early  plot  E  and  the  late  plots  is  favorable  to  the 
early  plot  in  almost  the  same  amounts  as  those  given  for  A.  The 
total  yield  of  corn  and  fodder  of  the  early  plot  C  was  less  than  that 
of  each  one  of  the  late  plots,  but  when  the  production  of  corn  alone 
is  compared,  the  plot  C  has  a  difference  of  yield  in  its  favor  ranging 
between  18  and  113.5  pounds.  Plot  A  produced  more  fodder  than 
each  one  of  the  late-plowed  plots,  while  the  early  plot  C  fell  in  its 
fodder  production  more  than  200  pounds  below  that  of  each  of  the 
late  plots.  The  amount  of  fodder  from  the  early  plot  E  is  less  than 
that  from  each  of  the  late  plots  B  and  F,  but  it  is  70  pounds  more 
than  the  yield  recorded  for  the  late  plot  D.  From  the  section 
“Grand  Total”  of  this  table  it  will  also  be  seen  that  the  yield  is 
higher  for  the  early  than  for  the  late  spring  plowed  land.  Here  the 
difference  against  the  late-plowed  land  is  as  follows :  Corn  and 
fodder,  715.5  pounds,  corn,  683.5  pounds,  and  fodder,  32  pounds. 

CORN  YIELD  AS  AFFECTED  BY  STALKS. 

The  investigations  made  in  this  line  of  study  show  results  un¬ 
favorable  to  the  stalked  land.  It  will  be  noticed  from  Table  IV  that 
the  difference  in  yield  is  in  .all  cases  but  one  in  favor  of  the  unstalked 
land.  The  amount  of  corn  and  fodder,  corn  or  fodder,  recorded  in 
the  early  column  of  the  unstalked  land  is  always  more  than  that  found 
in  either  the  early  or  the  late  of  the  stalked.  The  same  is  true  when 
comparing  in  like  manner  the  records  from  the  late  column  of  the 
unstalked  with  those  from  the  late  or  early  of  the  stalked,  with  the 
only  exception  of  the  record  for  corn  which  is  higher  for  the  early 
plots  of  the  stalked  land.  But  the  total  yield  obtained  from  both 
fields  shows  a  well-marked  difference  in  favor  of  the  unstalked.  This 
amounts  to  1,058.5  pounds  of  corn  and  fodder.  Of  this  778  pounds 
are  fodder  and  280.5  pounds  are  corn.  Thus  the  rate  of  increase  of 
corn  yield  in  favor  of  the  unstalked  is  280.5  pounds  of  corn,  or  4.125 
bushels  per  acre,  that  is  $1.65  per  acre  with  corn  at  40  cents  per 
bushel. 

Of  the  683.5  pounds  of  corn,  making  up  the  total  difference  of 
corn  yield  in  favor  of  the  early-plowed  land,  418.5  pounds  were 
produced  by  the  early-plowed  plots  of  the  unstalked  field,  and  the 
remaining  265  pounds  were  produced  by  the  early-plowed  plots  of 
the  stalked ;  that  is,  the  difference  in  favor  of  the  early-plowed  un¬ 
stalked  land  is  153.5  pounds.  This  exceptional  fact  against  the 
stalked  land  is  probably  explained  by  the  soil  and  water  relations  to 

20 


organic  matter,  especially  when  we  have  a  very  dry  and  hot  season, 
A  large  number  of  the  cornstalks  plowed  under  at  the  beginning  of 
the  season  were  found  to  be  undecayed  at  the  time  of  cultivation. 

V.  COMPARATIVE  STUDY  OF  TABLES  AND  SUMMARY. 


The  following  table  shows  by  plots  the  relation  between  moisture 
and  crop  yields.  (From  Tables  I  and  IV) : 


Plot. 

Surface  three  feet. 
Seasonable  Ave.  per  cent, 
moisture. 

Corn  and  Fod. 

-  Corn  Yield  in  Pounds. 
Corn. 

Fodder 

Early .  . 

.A 

20.18 

4042 

1121 

2871 

C 

20.18 

3344 

955 

238£ 

E 

20.93 

3800 

1211 

2589 

Late .  . . 

.  .B 

19.38 

3545 

875.5 

2670 

D 

19.03 

3360.5 

841.5 

2519 

F 

20.19 

3565 

937 

2628 

From  this  table  it  will  be  seen  that  the  moisture  content  through¬ 
out  the  season  in  the  early-plowed  plots  ranges  between  20.18  and 
20.93  per  cent.,  while  the  range  for  that  of  the  late  plowed  is  between 
19.03  and  20.19  per  cent.  The  range  of  the  corn  yield  from  the  early- 
plowed  land  is  between  955  and  1211  pounds,  while  that  of  the  late 
plowed  is  between  841.5  and  937  pounds.  It  should  be  noticed  that 
in  the  set  of  early  plots,  the  plot  E  contains  the  greatest  amount  of 
moisture  and  also  has  the  greatest  corn  production.  The  same  is 
true  with  the  late  plots  in  the  case  of  F.  The  yield  of  corn  of  each 
plot  of  the  earlv  set  was  greater  than  the  yield  from  any  one  of  the 
late  plots,  and  the  moisture  of  the  early  plots  was  greater  than  that 
of  the  late  plots. 

The  following  table  shows  by  depths  the  relation  between  the 
seasonable  average  of  moisture  content,  the  seasonal  average  of  avail¬ 
able  nitrogen  and  the  soil  temperature : 


Surface 

Foot. 

Second  Foot. 

Third 

Foot 

Early. 

Late. 

Early. 

Late. 

Early. 

Late. 

Per  cent,  of  moisture 

21.64 

20.44 

21.56 

20.53 

20.38 

19.92 

Nitrogen  in  p.  p.  mil¬ 
lion  . 

4.51 

2.83 

1.48 

1.44 

1.00 

0.73 

Mean  temperature.. 

68.76° 

70.41° 

66.17° 

66.75° 

62.79° 

64.42' 

From  this  table  it  will  be  seen  that  the  moisture  content  and  the 
amount  of  nitrogen  are  higher  in  the  early-plowed  plots,  while  the 
temperature  is  highest  with  the  late  plowed.  This  is  true  for  all 
depths.  It  will  also  be  seen  that  there  is  a  gradual  decrease  of  the 
moisture  content  of  the  early-plowed  plots  in  each  of  the  respective 
depths,  and  the  same  is  true  of  the  nitrogen  and  temperature.  In 
the  case  of  the  late-plowed  land  the  same  is  true  for  the  nitrogen  and 
temperature  and  more  or  less  true  for  the  moisture. 

21 


For  the  surface-two  feet,  the  moisture  content  is  21.61  and  20.48, 
the  nitrogen,  3  and  2.14,  and  average  mean  temperature  67.46°  and 
68.58°  for  the  early  and  late  plots  respectively. 

The  following  table  of  the  surface-three  feet  shows  the  seasonal 
average  of  moisture,  nitrogen  and  soil  temperature  as  related  to  the 
crop  yield : 

Early.  Late. 


Moisture  per  cent .  21.20 

Nitrogen  .  2.33 

Average  mean  temperature....  65.90° F. 

Crop  . 11,186 

Corn  .  3,337 

Fodder  .  7,849 


20.29 

1.67 

66.52°F. 

10,470.5  (pounds) 
2,653.5 
7,817 


This  table  is  a  strong  confirmation  of  what  has  been  shown  in 
the  other  tables  and  it  further  shows  that  the  higher  amount  of 
moisture  and  nitrogen  in  the  early  plots  is  followed  by  an  increase 
in  the  crop  yield. 

The  following  table  summarizes  the  differences  in  favor  of  the 
early-plowed  land :  (Expressed  in  seasonal  averages  and  pounds.) 


1st  Ft. 

2d  Ft. 

3d  Ft. 

Sf.  2  ft. 

Sf.  3  ft. 

Moisture  . 

1.20 

1.03 

.46 

1.13 

.91 

Nitrogen . 

1.68 

0.04 

.27 

.86 

.66 

Crop . 

715.5 

Corn . 

683.5 

Fodder . 

32. 

The  temperature, 

however,- 

was  in 

favor  of  late  plots. 

Mean  temperature.  .  . 

1.65° 

.58° 

1.63° 

Av.  mean  temperature 

1.12° 

.62°(F.) 

SUMMARY. 

The  object  of  this  investigation  was  to  determine  the  influence  of 
early  and  late  spring  plowing  upon  crop  production.  The  study  was 
carried  along  the  lines  of  soil  moisture,  available  nitrogen  and  soil 
temperature.  The  results  found  show: 

First.  That  the  crop  yield  from  the  early-plowed  land  is  more 
than  that  from  the  late,  at  the  rate  of  6.6  bushels  per  acre. 

Second.  That  there  is  a  very  strong  concordance  between  the 
yield  per  acre  and  by  plots,  and  the  amount  of  moisture  per  cent,  and 
available  nitrogen  found  in  the  soil  during  the  season. 

Third.  That  the  moisture-holding  power  of  soils  is  greater  with 
the  early-plowed  land  at  one,  two  and  three  feet  in  depth  than  that 
of  the  late,  the  greatest  difference  in  its  favor  being  found  in  the 
surface  foot. 


22 


Fourth.  That  when  the  moisture  content  of  this  particular  soil 
falls  below  12  per  cent.,  the  leaves  of  many  plants  curl  early  in  the 
day,  and  the  plant  turns  a  yellowish  color  and  is  more  or  less  checked 
in  its  growth. 

Fifth.  That  nitrification  takes  place,  with  a  gradually  decreasing 
intensity,  at  one,  two  and  three  feet  in  depth. 

Sixth.  That  the  seasonal  average  amount  of  available  nitrogen 
found  for  the  early-plowed  land  in  the  surface-foot  is  twice  that 
found  for  the  late  at  the  same  depth. 

Seventh.  That  the  available  nitrogen  in  the  surface-foot  of  the 
early-plowed  field  is  four  times  that  found  in  either  the  second  or 
third  foot,  early  or  late  land.* 

Eighth.  That  the  mean  soil  temperature  for  the  early-plowed 
land  is  in  all  cases  during  the  entire  season,  lower  than  that  found 
for  the  late  plowed. 

Ninth.  That  the  low  mean  soil  temperature  found  for  the  early- 
plowed  land  is  accompanied  throughout  the  season  by  a  greater 
amount  of  moisture  and  available  nitrogen  than  is  the  case  with  the 
late  plowed  which  has  the  higher  temperature. 

Tenth.  That  in  many  cases  a  high  temperature  is  followed  by 
a  high  rate  of  nitrification,  while  in  others  it  is  not,  thus  suggesting 
that  the  process  of  nitrification  i^  more  or  less  dependent  upon  what 
may  be  called  the  rate  relation  between  the  water  content  and  the 
temperature  of  the  soil,  provided  other  factors  are  favorable. 


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